Insect controlled pollination in Japanese plum (Prunus salicina Lindl.)

Trials were performed in a commercial orchard of self-incompatible plum, whose pollination and fruit yield often are a real problem in this early blooming crop. For this reason we introduced in the orchard honey bees, mason bees, and bumble bees. The efficiency of pollinator insects was evaluated in the open field by counting-for 3 h a day in five sampling areas of the orchard-the number of visits to the flowers of the main cultivar, No bumble bees were detected visiting the flowers of the main cultivar. The other two pollinators. showed a foraging activity which decreases by increasing the distance from their respective starting points: In each sampling area, the total number of visits was strongly related to fruit number and total yield. No significant differences were detected regarding fruit quality. Fruit yield of the most visited areas was very close to that obtained after mechanical pollination by pollen spray. Pollination was also performed on caged trees, using the different insects separately in order to evaluate their respective efficiency. (C) 1998 Elsevier Science B.V.